Strapping tools



F. s. RANsoM I STRAPPING TOOLS May 11, 1965 4 Sheets-Sheet 1 Filed Jan. 25, 1963 I lnvenlorguu.

. y 2 E 2 E Attorney May 11, 1965 F. s. RANSOM 3,182,690

STRAPPING TOOLS Filed Jan. 23, 1963 4 Sheets-Sheet 2 Inventor A llorney 1 y 11, 1965 F. s. RANSOM 3,182,690

STRAPPING TOOLS Filed Jan. 23, 1963 4 Sheets-Sheet 3 Inventor AL A Horn 2 y May 11, 1965 F. s. I RANSOM 3,182,690

STRAPPING 'rooL.

Filed Jan. 23, 1963 lnver llor Attorney 4 Sheets-Shet 4 United States Patent C) 3,182,690 STRAPPING TOOLS Frank S. Ransom, Birmingham, England, assignor to Fredlr. A. Power & Sons Limited, Birmingham, Warwick, England, a British company Filed Jan. 23, 1963, Ser. No. 253,312 Claims priority, application Great Britain, Feb. 17, 1962, 6,213/ 62 Claims. (Cl. 140-936) This invention relates to a power-operated tool for securing a wire strap round a package such as a carton, box, case, or the like, and is concerned with the type of tool which is to be used with a generally fiat section wire known as .ribbon wire. The tool operates to secure the twoends of the wire together after it has been passed round the package by twisting the two ends upon one another and this is performed when the two ends of the wire are lying in a radial slot in a rotatable twister pinion. Owing to the section of the wire and its inherent resilience, it is necessary to give a certain amount of over twist so that when the wire is released from the "twister pinion and tends to recover slightly, it will finish with the portions of the wire extending from the twisted part, lying in flat or substantially flat relationship with the surface of the package.

Thus, it is necessary to arrange for the twister pinion to make a partial rotation beyond the set number of complete rotations which make up the twist and when the tool is being used with wire in it the inherent resilience in the wire will reverse the direction of rotation of the twister pinion after the'drive has been stopped so as to bring the slot in the twister pinion back into register with the guide slots in the tool to enable the wire to be ejected, but there is always the occasion when the tool will be operated without any wire in it and such case the twister pinion would not be returned and would be out of register when it was again desired to use the tool.

The object of the present invention is to provide control means which will operate to bring the twister pinion back into its correct position of register with the tool after the required degree of over twist has been applied so that the twister pinion will always be returned to its correct position irrespective of whether the tool is operated without wire in it or with wire in it.

According to the invention there is provided a strapping tool of the type above referred to wherein the drive to the twister pinion includes a driving gear wheel having a blank portion from which teeth are absent and wherein there is provided a separate control gear which is driven from the twister pinion during the twisting operation and which acts upon control spring means to stress such. spring means during the twisting operation whereby when the drive to the twister pinion is interrupted due to the blank portion on the driving gear, the spring means acts to reverse the direction of rotation of the control gear and thereby cause a reverse rotation of the twister pinion.

The driving gear and control gear may conveniently be disposed side-by-side upon a common axis and both being in mesh with the twister pinion and the gearing arrangement may be such that the control gear advances on the driving gear during the twisting operation.

The spring means may be arranged so that it is stressed by means of a member fixed to the control gear so as to rotate therewith and act 'upon another member to move this bodily and stress the spring means.

Alternatively the spring means may be connected between a member fixed to the control gear and a member rotating with the driving gear so that as the control gear advances on the driving gear the spring means is stressed.

3,182,690 Patented. May 11, 1965 Preferably, some form of stop means is provided to limit the amount of reverse rotation of the control gear.

In the following embodiments of the invention which are described by way of example the details of the driving motor and driving gear in the tool, and details of other parts such as the means for gripping and tensioning the wire, are not described as these form no part of the present invention and the construction and operation of such parts is generally of a known nature.

Two embodiments are illustrated in the accompanying drawings wherein:

FIGURE 1 is a plan view partly in section of the tool embodying the invention.

FIGURE 2 is a front elevation partly in section.

FIGURE 3 is a detailed view of the driving gear.

FIGURE 4 is an end view looking at the right-hand end of the control disc in FIGURE 2.

FIGURE 4A is an end elevation and section of a control disc.

FIGURE 4B is an end elevation and front view of the yoke member.

FIGURE 40 is a plan view of the yoke member.

FIGURE 5A is an end view corresponding to FIGURE 4 but showing an alternative arrangement of control disc.

FIGURE 5B is a front view of this alternative control disc.

FIGURE 5C is a plan view of a detail of the arrangement of FIGURE 5A.

The various parts of the tool are mounted upon a common base plate 10 which has a flat or substantially flat underside to rest upon the package which is being strapped and on its upper face this base plate has a pair of spaced apart upstanding pillars 11 each of which houses a bearing for the ends of the main shaft 12 upon which the driving gear 13 and control gear 14 are mounted.

The driving gear 13 has secured to one side thereof, a further gear wheel 15 which is coaxial therewith and which is in mesh with a pinion 16 on the end of the driving shaft 17 for the power tool (e.g. an air turbine) which supplies the drive for the twister pinion 18 and on its opposite face the driving gear 13 has an axially extending boss 19 upon which the control gear 14 and associated parts are loosely mounted.

The twister pinion 18 is mounted in suitable hearings on the base plate 10 and is disposed below the driving gear 13'and control gear 14 both of which mesh with the teeth on the outside of the twister pinion and the driving gear 13 has a portion 20 of its periphery of blank form provided by removing a predetermined number of teeth. The remaining teeth on the driving gear are slightly greater in number than the number of teeth on the control gear 14 so that as the driving gear rotates the twister pinion 18, this in turn rotates the control gear 14 in the same direction as the driving gear, the control gear 14 advancing on the driving gear 13.

As mentioned above, the control gear is loosely mounted upon a bearing sleeve 21 provided on the aforesaid boss 19 of the driving gear and on its face remote from the driving gear, the control gear has secured thereto, a control disc 22 which is of part-circular form, the major part of the circumference of this disc being of circular form but the remainder thereof being of cam form which provides two flats 23 and a convex portion 24 in between the two flats and. of considerably less radius of curvature than the remainder of the disc.

A control block 25 is mounted about the exterior of the control disc and this block is in the form of a generally U shaped yoke which is lying on its side, the

internal surface 26 of the yoke being of part-circular form to conform to the part-circular circumference of the control disc 22 and arranged concentrically therewith so that the control disc can rotate within this yoke. At the closed end ofthe yoke there is formed two outwardly projecting ears 27 which are spaced apart and a eg 28 which is carried at the upper end of a bracket .(not shown) fixed to the base plate en'ga'ges between these ear-s27 to prevent the yoke 25 from having any rotational movement when the drive is operating.

Each leg 28A of the yoke has a'rod 29 fixed in its free end and extending outwardly therefrom, the two rods being thus spaced apart one above the other and extending in the horizontal direction and a bridge piece 30 extends between these rodseach end of the bridge piece being slotted to engage slidably over'its associated rod.

Each rod'29 is also provided with a coiled spring 3-1 which is mounted about the rod and is. held between a nut screwed on the rod at .the one end and at the other end by the rear face of the adjacent end of the bridge piece 30. Thus, the bridge piece is slidable along the two rods to compress the two springs and on its forward face the bridge piece has two flats 32 spaced apart and joined by a concave surface, .andthese two fiats engage the corresponding flats 23 on the control disc 22 when the jparts of the tool, are in the ready position with the twister pinion in its correct position. of register.

The control disc 22 also has mounted thereon, a cam member 33 which is in the form of a small block having one end of bifurcated form rotatably embracing the main shaft 12 and-fixed near'the other end'to the outside face of the control disc so that as the control disc rotates this cam also rotates in radial fashion about the axis of the main shaft.

A stop member is mounted on the yoke and this is in the fornrof an arm 34 which at its upper end is pivotally mounted on the upper leg of the yoke and has its lower end 35 normally disposed in the path ofmovement of the outer end of the cam 33 and a spring mounted in a hole 36 in the upper leg of the yoke presses against the upper end of this arm 34 so as normally to holdit in the position in which its lower end comes into engagement with the face of the cam to prevent reverse rotation of the control disc.

When the tool is in the ready position, the twister pinion is in its normal position of register with its slot disposed horizontally and in this position the control disc 22 has its two flats 23 engaging the flats 32 of the bridge piece so that the springs 31 on the two rods of the yoke are under their minimum stress. Also the cam 33 fixed to the control disc is in the position in which it is hearing against the lower end of the stop arm 34 and the direction of rotation during the twisting operation is such that the cam will move away from this stop arm. When the power tool is operated, the driving gear 13' commences to rotate the twister pinion 18 the required number of full turns plus a partial turn for the over twist and at the same time the rotation of the twister pinion drives the control gear 14 and this causes the control disc to rotate. When the control disc rotates, one of its flats 23 will bear against the bridge piece whilst the other flat will move away from the bridge piece and thus the bridge piece will commence to be moved away from the control disc and compress the springs about the two rods but owing to the non-circular form of the control disc, the bridge piece will be tilted as it is slidden along the two rods (see FIGURE 4).

The control disc will complete one full rotation and the cam 33 on the control disc will snap past the stop arm 34 just before the end of this full rotation by pushing the stop arm back against its loading spring and thus a 7 position will be reached corresponding to the initial position in which the bridge piece is once again resting with its. two flats. engaging the flats of the control disc.

Owing however, to the fact that the control gear 14 advances on the driving gear 13, there will be a further partial rotation of the control disc before the driving gear reaches the point at which its blank portion comes into register with the twister pinion and thereafter position drive to the twister pinion ceases. V

This further partial rotation of the control disc will have caused the bridge me1nber'30 to be 'forfced'out'wardly again and tilted somewhat 'so' as to'compress" one of the springs more'than'the other and when the driving force is removed due to the blank portion of the driving gear coming into effect, the out-of-balance position of the bridge piece provides a resultant returning force acting upon the control disc to move this in the reverse difection of rotation and therefore the control disc will reverse its direction of rotation for-a srnall'arnount until its earn 33 comes up against the lower end .35 of the stop arm 34 and any further rotation isprevented.

This reverse rotation of the control disc'22 causes reverse rotation of the control gear 14 which, being in mesh with the twister pinion also returns the twister pinion back to its original position in which its slot is in the horizontal direction and'in register'with the remaining parts of the tool.

Referring to the modified 'form of control disc and associated parts shown in FIGURES 5A, 5B and SC, in this modified arrangement, the driving gear 13 is keyed to the main shaft '12 so that asthe driving gear rotates, the shaft 12 is rotated and in this case the control disc 4%) which is secured to the outer face of the control gear 14 is of different form to that described in thefi'rst embodiment.

This control disc 40 is of circular form except for the provision of a right angled notch 41 cut out of itsperiphery and there are'provided two pegs 42 fixed in the control disc and projecting outwardly from the outer face thereof. H v u U The shaft 12 has secured th ereto by means of grub screws 43 a block 44 which has two integrally formed outwardly projecting'arms 45 and between each one of these arms 45- and a peg 42 on the control disc there is connected-a'tension spring 46. I w v I The base plate 10 or the tool hasfixed thereto a block with upstanding ears 47 between which there is pivotally mounted one end-of a stop lever 48 and this lever is spring-urged upwardly by as'mall spring (not shown in the drawings) so that normallyits free end ispressed against the periphery of the control disc 40. When the control discrotates in the direction of the arrow in FIG- URE 5A,the end of the lever 48 becomes disengaged from "the notch 41 in -the control disc 40 and remains spring .pressed'against the periphery of the control disc during its rotation. When reverse rotation of the control disc takes place the end of the lever 48 engages in the notch 41 when this'comes round and thus acts as a stop to limit'the extent of reverse-rotation of the control disc 40.

The embodiment above described operates in substantialiy the same fashion as the first described embodiment, :as it will be appreciated that when the control disc 40 rotates it does so in advance ofthe driving gear 13 and, therefore, in advance of the rotation ofshaft '12 and its fixed block 44, so that the pegs 42, having an angular velocity greater than the arms 45 cause corresponding extension of the springs 46. Thus when the driving gear halts, the stress in the springs 46 produce a reverse rotation in the control disc 40 until this is halted by the engiagement of the lever 48 in the notch 41 of the control sc.

What I claim then is:

1. A strapping tool for securing a strap round a package, comprising a twister pinion with an open ended radial slot for receiving overlapping parts of the strap, a toothed driving gear wheel in mesh with the pinion and having a blank port on fr m which teeth are absent, a toothed control gear wheel coupled to said twister pinion, and

spring means operatively coupled to said control gear rupted by the blank portion of the driving gear wheel.

2. A strapping tool for securing a strap round a package, comprising. a twister pinion with an open ended radial slot for receiving overlapping parts of the strap, a toothed driving gear wheel and a toothed control gear Wheel mounted for rotation relatively to one another on a common axis and both in mesh with said twister pinion, a smaller number of teeth on said control gear wheel than on said driving gear wheel whereby when the twister pinion is driven in one sense by the driving gear wheel the control gear wheel will advance relatively to the driving gear wheel, the driving gear wheel having a blank portion from which teeth are absent, and there being provided spring means operatively coupled to the control gear wheel to be stressed thereby when the control gear wheel advances relatively to the driving gear wheel and to drive the control gear wheel and the twister pinion in the reverse sense when the drive to the twister pinion by the driving gear wheel is interrupted by the blank portion of the driving gear wheel.

3. A strapping tool for securing a strap round a package, comprising a twister pinion with an open ended radial slot for receiving overlapping parts of the strap, a toothed driving gear wheel and a toothed control gear wheel mounted for rotation relatively to one another on a common axis and both in mesh with said twister pinion, fewer teeth on said control gear wheel than on said driving gear Wheel whereby when the twister pinion is driven in one sense by the driving gear wheel the control gear wheel will advance relatively to the driving gear wheel, 1

means, and a second member actuatable by said'first member to stress said spring means when the control gear wheel advances relatively to the driving gear wheel, whereby the stressed spring will drive the control gear wheel and the twister pinion in the reverse sense when the drive to the twister pinion by the driving gear Wheel is interrupted by the blank portion of the driving gear wheel.

4. A strapping tool for securing a strap round a package, comprising a twister pinion with an open ended radial slot for receiving overlapping parts of the strap, a toothed driving gear wheel and a toothed control gear wheel mounted for rotation relatively to one another on a common axis and both in mesh with said twister pinion, fewer teeth on said control gear wheel than on said driving gear wheel whereby when the twister pinion is driven in one sense by the driving gear wheel the control gear wheel will advance relatively to the driving gear wheel, the driving gear wheel having a blank portion from which teeth are absent, and there being provided a first member fixed to so as to turn with the control gear wheel, a second member rotatable with the driving gear wheel and spring means connected between said first and second members to be stressed when the control gear wheel advances relatively to the driving gear wheel and to drive the control gear wheel and the twister pinion in the reverse sense when the drive to the twister pinion by the driving gear wheel is interrupted by the blank portion of the driving gear wheel.

5. A strapping tool as claimed in claim 4, in which saidfirst member is a control disc fixed to a face of the control gear wheel, the driving gear wheel is keyed to a main driving shaft, said second member is an arm which is fixed to said main driving shaft, and said spring means is connected between said arm and said control disc.

References Cited by the Examiner UNITED STATES PATENTS 9/26 Wolff 93.6

CHARLES W. LANHAM, Primary Examiner. 

1. A STRAPPING TOOL FOR SECURING A STRAP ROUND A PACKAGE, COMPRISING A TWISTER PINION WITH AN OPEN ENDED RADIAL SLOT FOR RECEIVING OVERLAPPING PARTS OF THE STRAP, A TOOTHED DRIVING GEAR WHEEL IN MESH WITH THE PINION AND HAVING A BLANK PORTION FROM WHICH TEETH ARE ABSENT, A TOOTHED CONTROL GEAR WHEEL COUPLED TO SAID TWISTER PINION, AND SPRING MEANS OPERATIVELY COUPLED TO SAID CONTROL GEAR WHEEL TO BE STRESSED THEREBY WHEN THE TWISTER PINION AND THE CONTROL GEAR WHEEL ARE DRIVEN IN ONE SENSE BY SAID DRIVING GEAR WHEEL AND TO DRIVE THE CONTROL GEAR WHEEL AND THE TWISTER PINION IN THE OPPOSITE SENSE WHEN THE DRIVE TO THE TWISTER PINION BY THE DRIVING GEAR WHEEL IS INTERRUPTED BY THE BLANK PORTION OF THE DRIVING GEAR WHEEL. 